Implantable medical devices and related delivery systems

ABSTRACT

The present disclosure describes medical devices comprising implantable expandable implants, such as stent-grafts. Such devices can comprise a constraining line. The constraining line can surround the proximal end of the expandable implant, and assist in positioning and deployment of the expandable implant within the body of the patient.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/572,263, filed Dec. 16, 2014, which claims the benefit of U.S.Provisional Application 61/773,981, filed Mar. 7, 2013, both of whichare incorporated herein by reference in their entireties for allpurposes.

FIELD

The present disclosure relates generally to implantable medical devicesand, more specifically, to stent-grafts removably coupled to deliverydevices.

BACKGROUND

Implantable medical devices are frequently used to treat the anatomy ofpatients. Such devices can be permanently or semi-permanently implantedin the anatomy to provide treatment to the patient. Frequently, thesedevices, including stents, grafts, stent-grafts, filters, valves,occluders, markers, mapping devices, therapeutic agent delivery devices,prostheses, pumps, bandages, and other endoluminal and implantabledevices, are inserted into the body at an insertion point and deployedto a treatment area using a catheter.

Typically, these implantable devices are attached to the catheterassembly and directed through the vasculature of the patient to thedesired treatment area. Once the implantable device reaches thetreatment area, the device is properly oriented and deployed to providetreatment. Such orientation and deployment is actuated by a physicianusing controls outside of the body of the patient. Accordingly, there isa need for medical devices with improved maneuverability and positioningwithin the vasculature of the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosure,and together with the description, serve to explain the principles ofthe disclosure, wherein;

FIG. 1 illustrates a perspective view of a medical device in accordancewith the present disclosure;

FIG. 2 illustrates a partial perspective view of a medical device inaccordance with the present disclosure;

FIGS. 3A and 3B illustrate perspective views of medical devices inaccordance with the present disclosure; and

FIGS. 4A and 4B illustrate perspective views of medical devices inaccordance with the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Persons skilled in the art will readily appreciate that various aspectsof the present disclosure may be realized by any number of methods andsystems configured to perform the intended functions. Stateddifferently, other methods and systems can be incorporated herein toperform the intended functions. It should also be noted that theaccompanying drawing figures referred to herein are not all drawn toscale, but may be exaggerated to illustrate various aspects of thepresent disclosure, and in that regard, the drawing figures should notbe construed as limiting.

As used herein, “medical devices” can include, for example, stents,grafts, stent-grafts, filters, valves, occluders, markers, mappingdevices, therapeutic agent delivery devices, prostheses, pumps,bandages, and other endoluminal and implantable devices that areimplanted, acutely or chronically, in the vasculature or other bodylumen or cavity at a treatment region.

The medical devices, support structures, coatings, and covers, describedherein, can be biocompatible. As used herein, “biocompatible” meanssuited for and meeting the purpose and requirements of a medical device,used for long- or short-term implants or for non-implantableapplications. Long-term implants are generally defined as devicesimplanted for more than about 30 days, while short-term implants aregenerally defined as devices implanted for less than about 30 days.

As used herein, “proximal” indicates a position closer to the heart ofthe patient, or to a portion of a device that, when implanted, is closerto the heart of the patient than another portion of the device. “Distal”indicates a position farther from the heart of the patient, or to aportion of a device that, when implanted, is farther from the heart ofthe patient than another portion of the device. Implanted devices havingtubular or rod-like shape comprise a distal end, a distal portion, amedial portion, a proximal portion, and a proximal end moving from theend farthest from the heart to the end closest to the heart.

As used herein, a “sleeve” can include any enclosure constraining anexpandable device. In various embodiments, a sleeve can comprise a sheetof material wrapped around an expandable device in a collapsed,intermediate, or treatment configuration.

As used herein, the term “constrain” means: (i) to limit expansion,occurring either through self-expansion or assisted expansion, of thediameter of an expandable implant; or (ii) to cover or surround, but nototherwise restrain, an expandable implant such as for storage orbiocompatibility reasons and/or to provide protection to the expandableimplant and/or the vasculature.

As used herein, “deployment” refers to the actuation of a device at atreatment site, such as for example, the release and/or removal of asleeve from a self-expanding device to allow the device to expand. Thedeployment process can be in stages, such as for example, a first stagecomprising the release of a sleeve to a configuration suitable toconstrain the expandable device only to an intermediate configuration,and a second stage comprising the removal of the sleeve altogether fromthe device.

Various embodiments of the present disclosure comprise a catheterassembly configured to deliver an expandable implant to a treatment areaof the vasculature of a patient. In accordance with embodiments of thedisclosure, an expandable implant, such as a stent-graft, is constrainedby one or more sleeves concentrically surrounding the expandableimplant. The expandable implant can be maintained in a desiredorientation and/or position relative to the catheter assembly by aconstraining line. Benefits of expandable implants in accordance withthe present disclosure can include improved maneuverability of theexpandable implant within the vasculature of a patient, and improveddeployment characteristics.

With initial reference to FIG. 1, a catheter assembly 100 in accordancewith the present disclosure is illustrated. Catheter assembly 100comprises a catheter shaft 102. An expandable implant 104 is positionedat a proximal end of and removably coupled to catheter shaft 102 by aconstraining line 120. Expandable implant 104 is concentricallysurrounded by at least one constraining sleeve, such as sleeve 110.

In various embodiments, expandable implant 104 comprises a stent-graft.Conventional stent-grafts are designed to dilate from their deliverydiameter, through a range of intermediary diameters, up to a maximum,often pre-determined functional diameter, and generally comprise one ormore stent components with one or more graft members displaced overand/or under the stent.

In various embodiments, expandable implant 104 comprises one or morestents 106. In various embodiments, stent 106 comprises a biocompatiblematerial. For example, stent 106 can be formed from metallic, polymericor natural materials and can comprise conventional medical gradematerials such as nylon, polyacrylamide, polycarbonate, polyethylene,polyformaldehyde, polymethylmethacrylate, polypropylene,polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride,polyurethane, elastomeric organosilicon polymers; metals such asstainless steels, cobalt-chromium alloys and nitinol, and biologicallyderived materials such as bovine arteries/veins, pericardium andcollagen. Stent 106 can also comprise bioresorbable materials such aspoly(amino acids), poly(anhydrides), poly(caprolactones),poly(lactic/glycolic acid) polymers, poly(hydroxybutyrates) andpoly(orthoesters). Any material that is biocompatible and providesadequate support for expandable implant 104 is in accordance with thepresent disclosure.

Stent 106 can comprise, for example, various configurations such asjoined rings, cut tubes, wound wires (or ribbons) or flat patternedsheets rolled into a tubular form. However, any configuration of stent106 that can be implanted in and provide support to the vasculature of apatient is in accordance with the present disclosure.

In various embodiments, stent 106 can comprise one or more anchors 116.For example, one or more anchors 116 can be located at or near theproximal end of stent 106. In such configurations, anchors 116 canengage and attach to the vasculature of the patient to maintainexpandable implant 104 in a desired position within the vasculature. Theuse of any number and configuration of anchors 116 is within the scopeof the present disclosure.

In various embodiments, expandable implant 104 comprises a graft member108. Graft member 108 can comprise a biocompatible material thatprovides a lumen for blood flow within a vasculature. For example, graftmember 108 can comprise a composite material having a flexible matrix.In such configurations, the flexible matrix can comprise, for example,expanded polytetrafluoroethylene (ePTFE), pebax, polyester,polyurethane, fluoropolymers, such as perfouorelastomers and the like,polytetrafluoroethylene, silicones, urethanes, ultra high molecularweight polyethylene, aramid fibers, silk, and combinations thereof.Other flexible matrices can include high strength polymer fibers such asultra high molecular weight polyethylene fibers (e.g., Spectra®, DyneemaPurity®, etc.) or aramid fibers (e.g., Technora®, etc.). Any graftmember 108 that provides a sufficient lumen for blood flow within avasculature is in accordance with the present disclosure.

In various embodiments, graft member 108 can comprise a compositematerial having a flexible matrix and an elastomeric component. Anelastomeric component can comprise, for example, aperfluoroalkylvinylether (PAVE), such as perfluoromethylvinylether(PMVE) as described in U.S. Pat. No. 7,462,675 (hereby incorporated byreference), perfluoroethylvinylether (PEVE), orperfluoropropylvinylether (PPVE). Other biocompatible polymers which canbe suitable for use in embodiments can include, but are not limited to,the group of urethanes, silicones, copolymers of silicon-urethane,styrene.isobutylene copolymers, polyisobutylene,polyethylene-co-poly(vinyl acetate), polyester copolymers, nyloncopolymers, fluorinated hydrocarbon polymers and copolymers or mixturesof each of the foregoing. In such configurations, the flexible matrix isimbibed with the elastomeric component. However, any elastomericcomponent that is biocompatible and can be imbibed by a suitableflexible matrix is in accordance with the present disclosure.

With reference to FIG. 1, expandable implant 104 can be delivered to thetreatment area of a patient by a catheter assembly 100. In variousembodiments, expandable implant 104 is delivered into the body of apatient via catheter shaft 102. In such embodiments, expandable implant104 can be collapsed and/or compressed and positioned at the proximalend of catheter shaft 102. Expandable implant 104 can then be navigatedthrough the body of the patient to the treatment area.

In various embodiments, expandable implant 104 can comprise a radiallycollapsed configuration suitable for delivery to the treatment area ofthe vasculature of a patient. Expandable implant 104 can be constrainedin a radially collapsed configuration and mounted onto a delivery devicesuch as catheter shaft 102. The diameter of the expandable implant 104in the collapsed configuration is small enough for the implant to bedelivered through the vasculature to the treatment area. In variousembodiments, the diameter of the collapsed configuration is small enoughto minimize the crossing profile of catheter assembly 100 and minimizetissue damage to the patient. In the collapsed configuration, theexpandable implant 104 can be guided by catheter shaft 102 through thevasculature. Once expandable implant 104 is in position in the treatmentarea of the vasculature, it can be expanded to a radially expandedconfiguration.

In various embodiments, expandable implant 104 can comprise a radiallyexpanded configuration suitable for implanting the device in thetreatment area of a patient's vasculature. In the expandedconfiguration, the diameter of expandable implant 104 can beapproximately the same as the vessel to be repaired. In otherembodiments, the diameter of expandable implant 104 in the expandedconfiguration can be slightly larger than the vessel to be treated toprovide a traction fit within the vessel.

In various embodiments, expandable implant 104 can comprise aself-expandable device, such as a self-expandable stent-graft. Suchdevices dilate from a radially collapsed configuration to a radiallyexpanded configuration when unrestrained. In other embodiments,expandable implant 104 can comprise a device that is expanded with theassistance of a secondary device such as, for example, a balloon. In yetother embodiments, catheter assembly 100 can comprise a plurality ofexpandable implants 104. The use of a catheter assembly with any numberof expandable implants is within the scope of the present disclosure.

Various medical devices in accordance with the disclosure comprise asleeve or multiple sleeves. The sleeve or sleeves can constrain anexpandable implant device in a collapsed configuration for endoluminaldelivery of the implant to a treatment portion of the vasculature of apatient. For example, as illustrated in FIG. 1, catheter assembly 100comprises sleeve 110. Sleeve 110 surrounds and constrains expandableimplant 104 to a reduced diameter.

After delivery of the expandable implant to the treatment portion of thevasculature of the patient, the sleeve or sleeves can be unconstrainedin order to allow the expandable implant to expand to its functionaldiameter and achieve the desired therapeutic outcome. In variousembodiments, the sleeve or sleeves can remain implanted while notinterfering with the expandable implant. In other embodiments, thesleeve or sleeves can be removed from the body of the patient aftersuccessful deployment of the expandable implant.

In various embodiments, sleeves such as sleeve 110 can be formed from asheet of one or more materials wrapped or folded about the expandableimplant. While the illustrative embodiments herein are described ascomprising one or more tubular sleeves, sleeves of any non-tubular shapethat corresponds to an underlying expandable implant or that areotherwise appropriately shaped for a given application are also withinthe scope of the present disclosure.

In various embodiments, sleeves are formed by wrapping or folding thesheet of material(s) such that two parallel edges of the sheet aresubstantially aligned. Said alignment may or may not be parallel to orcoaxial with the catheter shaft of a catheter assembly. In variousembodiments, the edges of the sheet of material(s) do not contact eachother. In other embodiments the edges of the sheet of material(s)contact each. Any manner of forming a sleeve from a sheet of material iswithin the scope of the present disclosure.

In various embodiments, sleeves comprise materials similar to those usedto form a graft member. For example, a precursor flexible sheet used tomake the sleeve can be formed from a flattened, thin wall ePTFE tube.The thin wall tube can incorporate “rip-stops” in the form oflongitudinal high strength fibers attached or embedded into the sheet ortube wall.

The sheet of material(s) used to form the sleeve(s) can comprise aseries of openings, such that the openings extend from one edge of thesheet to the other. In such configurations, a coupling member can bewoven or stitched through the series of openings in the sheet ofmaterial(s), securing each of the two edges together and forming a tube.For example, in FIG. 1, catheter assembly 100 comprises a couplingmember 112 that engages with a plurality of holes 114 and secures theedges of sleeve 110 such that sleeve 110 maintains expandable implant104 in a reduced diameter.

In various embodiments, when the expandable implant is in positionwithin the vasculature, coupling member 112 can be disengaged from thesleeve or sleeves from outside of the body of the patient, which allowsthe sleeve(s) to open and the expandable implant to expand. As discussedabove, the expandable implant can be self-expanding, or the implant canbe expanded by a device, such as a balloon.

Coupling member 112 can comprise, for example, a woven fiber. In otherembodiments, the coupling member can comprise a monofilament fiber. Anytype of string, cord, thread, fiber, or wire that is capable ofmaintaining a sleeve in a tubular shape is within the scope of thepresent disclosure.

The coupling member or members can be disengaged from the sleeve orsleeves by a mechanical mechanism operated from outside of the body ofthe patient. For example, coupling member 112 can be disengaged byapplying sufficient tension to coupling member 112. In another example,a dial or rotational element of a catheter handle can be attached tocoupling member 112 outside of the body. Rotation of the dial orrotational element can provide sufficient tension to, displace anddisengage coupling member 112.

In various embodiments, disengaging a single coupling member that closesa single sleeve from the sleeve allows the expandable device to be fullyexpanded. For example, with reference to FIG. 1 catheter assembly 100can be used to deliver an expandable implant 104 to a treatment area ofa vasculature. In such configurations, sleeve 110 circumferentiallysurrounds expandable implant 104 and constrains it to a collapsedconfiguration. Once expandable implant 104 is in position relative tothe treatment area, coupling member 112 is disengaged from sleeve 110and sleeve 110 is released, allowing expandable implant 104 to expandfrom a collapsed configuration to a larger diameter.

In various embodiments, catheter assembly 100 further comprises aconstraining line 120. Constraining line 120 can, for example, assist insecuring expandable implant 104 to catheter shaft 102. In variousembodiments, constraining line 120 can be positioned on or near theproximal end of expandable implant 104. In other embodiments,constraining line 120 can be positioned at or near the distal, or at anyposition between the proximal and distal end, of expandable implant 104.Constraining line 120 can interact with expandable implant 104 andassist in maintaining a desired position and orientation of expandableimplant 104 in relation to catheter shaft 102. In such embodiments,constraining line 120 can improve maneuverability of expandable implant104 relative to the treatment area of the patient by, for example,allowing an operator to displace and orient expandable implant 104within the vasculature of a patient even after the implant has beenpartially or fully expanded. Further, constraining line 120 canconstrain and prevent the proximal end of expandable implant 104 fromcontacting and/or engaging the vasculature until full and finaldeployment is desired.

With reference to FIG. 2, in various embodiments, constraining line 120can interact with stent 106. Stent 106 can comprise a stent pattern 222having straight segments 224 and apices 226. In various embodiments,constraining line 120 can be woven through alternating straight segments224 and/or alternating apices 226 around the circumference of expandableimplant 104 at the proximal end and perpendicular to a longitudinal axisof expandable implant 104. In other embodiments, constraining line canbe woven through straight segments 224 and apices 226 at an anglerelative to the longitudinal axis of expandable implant 104. However,constraining line 120 can interact with expandable implant 104 in anymanner that will allow constraining line 120 to maintain expandableimplant 104 in a desired position and orientation relative to cathetershaft 102.

In various embodiments, expandable implant 104 is inserted into thevasculature of the patient in a collapsed configuration, whereinexpandable implant 104 is surrounded by sleeve 110 and held in a desiredposition relative to catheter shaft 102 by constraining line 120.Expandable implant 104 is then directed to a treatment area of thepatient. Upon reaching the treatment area, the implant is deployed. Invarious embodiments, deployment of expandable implant 104 comprisesremoving sleeve 110 and removing constraining line 120 from expandableimplant 104.

In various embodiments, constraining line 120 can include or form a loop230. In such embodiments, constraining line 120 can interact with orotherwise extend through the loop 230 to form a slip knot and travelfrom the proximal end of expandable implant 104 to the outside of thebody of the patient. Alternatively, loop 230 can comprise an end loop,such that when constraining line 120 passes through loop 230, it forms aslip knot. In such embodiments, constraining line 120 comprises a lineor wire looped into an end loop 230, thereby creating two segments. Bothsegments pass through loop 230 to form the slip knot, and then travelback along the length of the delivery device and outside of the patient.The resulting slip knot can extend about and releasably restrain theproximal end of the expandable implant 104 axially and/or radially withrespect to the catheter shaft 102.

Referring to FIG. 2, to release constraining line 120 from expandableimplant 104, the operator can release one of the segments ofconstraining line 120 and provide tension to the other segment indirection 232. By pulling the non-released segment of constraining line120, the released segment can travel in the direction 234, throughcatheter shaft 102, unwind along the segment of expandable implant 104through which it was woven, then travel back through and exit fromcatheter shaft 102. Although described in relation to a singleconstraining line 120 and loop 230, any number of constraining lines 120and loops 230 are within the scope of the present disclosure.

For example, catheter assembly 100 can further comprise a catheterhandle, and one or more segments of constraining line 120 can beremovably coupled to the catheter handle. In such embodiments, thecatheter handle can comprise a release button that, when activated,releases one segment of constraining line 120.

As illustrated in FIGS. 3A, 3B, 4A, and 4B, constraining line 120 canmaintain expandable implant 104 in a desired position relative tocatheter shaft 102 and can extend about and constrain the proximal endof the expandable implant 104 relative to the catheter shaft 102.

For example, with reference to FIGS. 3A and 3B, expandable implant 104can be positioned concentrically around catheter shaft 102. Asillustrated in FIG. 3A, constraining line 120 can surround the proximalend of expandable implant 104, pass through loop 230 to form the slipknot, and travel along the outside surface of catheter shaft 102. Asillustrated in FIG. 3B, after passing through loop 230, constrainingline 120 can pass through access hole 328 in catheter shaft 102 andtravel along the interior of catheter shaft 102 to the outside of thebody of the patient.

With reference to FIGS. 4A and 4B, expandable implant 104 can bepositioned adjacent and parallel to catheter shaft 102. For example, asillustrated in FIG. 4A, constraining line 120 can surround the proximalend of expandable implant 104, pass through loop 230 to form the slipknot, and travel along the outside surface of catheter shaft 102. Invarious embodiments, catheter shaft 102 can comprise one or moreretainers 430, which maintain constraining line 120 in a desiredposition and orientation relative to catheter shaft 102. As illustratedin FIG. 4B, after passing through loop 230, constraining line 120 canpass through access hole 328 in catheter shaft 102 and travel along theinterior of catheter shaft 102 to the outside of the body of thepatient. Although the above embodiments are described in detail, anyconfiguration of constraining line 120, catheter shaft 102, andexpandable implant 104 is within the scope of the present disclosure.

In various embodiments, constraining line 120 can assist in deploymentof expandable implant 104. For example, coupling member 112 can beremoved to allow sleeve 110 to open to its unconstrained diameter.Expandable implant 104 can then be expanded to its expandedconfiguration. In such embodiments, it may be desirable to remove sleeve110 by applying tension to and consequently retracting sleeve 110 fromthe body of the patient. However, the tension applied to sleeve 110 cancause portions of stent 106 to collapse, become displaced, or distort.For example, when tension is applied, the proximal end of stent 106 canbe pulled towards the distal end, displacing and/or deforming theproximal end. In various embodiments, constraining line 120 can beconfigured to resist such tension and maintain the proximal end in adesired position and location relative to catheter shaft 102.

In other embodiments, catheter assembly 100 can comprise multiplesleeves. In such configurations, a first sleeve constrains expandableimplant 104 in a collapsed configuration. By removing and/or activatinga first coupling member, the first sleeve can be removed and expandableimplant 104 can expand to a configuration having a larger diameter thanin the collapsed configuration.

In such embodiments, expandable implant 104 can be expanded from thecollapsed configuration to the intermediate configuration onceexpandable implant 104 has been delivered near the treatment area of thevasculature of a patient. The intermediate configuration can, amongother things, assist in properly orienting and locating the expandableimplant within the treatment area of the vasculature.

Catheter assembly 100 can further comprise a balloon. In suchembodiments, the balloon can assist in final deployment of expandableimplant 104 by, for example, being inflated within expandable implant104. With sufficient inflation, the balloon can force stent 106 to fullyexpand against the walls of the vasculature. In embodiments that utilizeanchors 116, the balloon can assist anchors 116 in engaging with thevasculature by forcing anchors 116 against the vessel walls.

In accordance with the present disclosure, in various embodiments, amedical device can comprise one or more coatings. In variousembodiments, the coatings comprise bio-active agents. Bio-active agentscan be coated onto a portion or the entirety of the stent and/or graftmember for controlled release of the agents once the device isimplanted. The bio-active agents can include, but are not limited to,vasodilator, anti-coagulants, such as, for example, warfarin andheparin. Other bio-active agents can also include, but are not limitedto agents such as, for example, anti-proliferative/antimitotic agentsincluding natural products such as vinca alkaloids (i.e. vinblastine,vincristine, and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e.etoposide, teniposide), antibiotics (dactinomycin (actinomycin D)daunorubicin, doxorubicin and idarubicin), anthracyclines, mitoxantrone,bleomycins, plicamycin (mithramycin) and mitomycin, enzymes(L-asparaginase which systemically metabolizes L-asparagine and deprivescells which do not have the capacity to synthesize their ownasparagine); antiplatelet agents such as G(GP) IIb/IIIa inhibitors andvitronectin receptor antagonists; anti-proliferative/antimitoticalkylating agents such as nitrogen mustards (mechlorethamine,cyclophosphamide and analogs, melphalan, chlorambucil), ethyleniminesand methylmelamines (hexamethylmelamine and thiotepa), alkylsulfonates-busulfan, nirtosoureas (carmustine (BCNU) and analogs,streptozocin), trazenes-dacarbazinine (DTIC);anti-proliferative/antimitotic antimetabolites such as folic acidanalogs (methotrexate), pyrimidine analogs (fluorouracil, floxuridine,and cytarabine), purine analogs and related inhibitors (mercaptopurine,thioguanine, pentostatin and 2-chlorodeoxyadenosine {cladribine});platinum coordination complexes (cisplatin, carboplatin), procarbazine,hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen);anti-coagulants (heparin, synthetic heparin salts and other inhibitorsof thrombin); fibrinolytic agents (such as tissue plasminogen activator,streptokinase and urokinase), aspirin, dipyridamole, ticlopidine,clopidogrel, abciximab; antimigratory; antisecretory (breveldin);anti-inflammatory: such as adrenocortical steroids (cortisol, cortisone,fludrocortisone, prednisone, prednisolone, 6α-methylprednisolone,triamcinolone, betamethasone, and dexamethasone), non-steroidal agents(salicylic acid derivatives i.e. aspirin; para-aminophenol derivativesi.e. acetaminophen; indole and indene acetic acids (indomethacin,sulindac, and etodalac), heteroaryl acetic acids (tolmetin, diclofenac,and ketorolac), arylpropionic acids (ibuprofen and derivatives),anthranilic acids (mefenamic acid, and meclofenamic acid), enolic acids(piroxicam, tenoxicam, phenylbutazone, and oxyphenthatrazone),nabumetone, gold compounds (auranofin, aurothioglucose, gold sodiumthiomalate); immunosuppressives: (cyclosporine, tacrolimus (FK-506),sirolimus (rapamycin), azathioprine, mycophenolate mofetil); angiogenicagents: vascular endothelial growth factor (VEGF), fibroblast growthfactor (FGF); angiotensin receptor blockers; nitric oxide donors;anti-sense oligionucleotides and combinations thereof; cell cycleinhibitors, mTOR inhibitors, and growth factor receptor signaltransduction kinase inhibitors; retenoids; cyclin/CDK inhibitors; HMGco-enzyme reductase inhibitors (statins); and protease inhibitors.

In various embodiments, various components of the devices disclosedherein are steerable. For example, during deployment at a treatmentsite, one or more of the elongated segments can be configured with aremovable steering system that allows an end of the elongated segment tobe biased or directed by a user. A removable steering system inaccordance with various embodiments can facilitate independentpositioning of an elongated segment and can provide for the ability of auser to accomplish any of the types of movements previously described,such as longitudinal movement, rotational movement, lateral movement, orangular movement.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the spirit or scope of the disclosure. Thus, itis intended that the present disclosure cover the modifications andvariations of this disclosure provided they come within the scope of theappended claims and their equivalents.

Likewise, numerous characteristics and advantages have been set forth inthe preceding description, including various alternatives together withdetails of the structure and function of the devices and/or methods. Thedisclosure is intended as illustrative only and as such is not intendedto be exhaustive. It will be evident to those skilled in the art thatvarious modifications can be made, especially in matters of structure,materials, elements, components, shape, size and arrangement of partsincluding combinations within the principles of the disclosure, to thefull extent indicated by the broad, general meaning of the terms inwhich the appended claims are expressed. To the extent that thesevarious modifications do not depart from the spirit and scope of theappended claims, they are intended to be encompassed therein.

1. (canceled)
 2. A medical device, comprising: a catheter shaft; anexpandable implant arranged on the catheter shaft and having a collapsedconfiguration, an expanded configuration, a proximal end, and a distalend; a primary sleeve having a proximal end, a distal end, a first edgeand a second edge, the primary sleeve wrapped around the expandableimplant such that the first edge and the second edge are parallel, theprimary sleeve releasably constraining the expandable implant in thecollapsed configuration; and a constraining line comprising a first endand a second end and forming a loop, the loop surrounding the distal endof the expandable implant, wherein the constraining line resists tensionapplied to the primary sleeve and maintains the distal end of theexpandable implant in a desired position relative to the catheter shaft.3. The medical device of claim 2, the primary sleeve comprising a seriesof openings extending along the first edge and the second edge from theproximal end to the distal end.
 4. The medical device of claim 3,further comprising a first coupling member engaging the series ofopenings and releasably securing the first edge and the second edge ofthe primary sleeve such that the expandable implant is maintained in thecollapsed configuration.
 5. The medical device of claim 2, furthercomprising a secondary sleeve configured to releasably constrain theexpandable implant in an intermediate configuration.
 6. The medicaldevice of claim 5, further comprising a second coupling member engagingthe secondary sleeve and releasably securing the secondary sleeve suchthat the expandable implant is maintained in the intermediateconfiguration.
 7. The medical device of claim 2, wherein the expandableimplant comprises a stent pattern including straight segments andapices, and wherein the constraining line is woven through alternatingstraight segments or apices around a circumference of the expandableimplant.
 8. The medical device of claim 7, wherein the constraining lineis woven through straight segments or apices at an angle relative to alongitudinal axis of the expandable implant.
 9. The medical device ofclaim 2, wherein the constraining line comprises an end loop and whereinthe first end and the second end of the constraining line pass throughthe end loop to form a slip knot.
 10. The medical device of claim 9,wherein the constraining line is removed by releasing the first end ofthe constraining line and applying tension to the second end of theconstraining line.
 11. The medical device of claim 2, wherein the firstedge and the second edge of the primary sleeve do not contact eachother.
 12. A medical device comprising: a catheter shaft; an expandableimplant comprising a collapsed configuration, an expanded configuration,and a proximal end; a sleeve having a first edge, a second edge, a firstseries of openings along the first edge and a second series of openingsalong the second edge, the sleeve configured to releasably constrain theexpandable implant in the collapsed configuration; a coupling memberwoven through the first and second series of openings and configured toreleasably secure the first and second edges of the retractable sleevetogether to maintain the expandable implant in the collapsedconfiguration, wherein the coupling member is releasable by pulling thecoupling member to release the edges of the sleeve and allow theexpandable implant to expand from the collapsed configuration to theexpanded configuration; and a constraining line forming a loop andhaving a first end and a second end, wherein the first end and thesecond end of the constraining line extend through the loop to form aslip knot surrounding the expandable implant, wherein the slip knot canbe tightened in response to tensioning of both the first and second endsof the constraining line to resist tension applied by the sleeve on theexpandable device during retraction of the sleeve following expansion ofthe expandable implant from the collapsed configuration to the expandedconfiguration.